AP Chemistry 1.4 Laws of Thermodynamics. Which of the following statements is true?
|AP Chemistry||Laws of Thermodynamics|
The Laws of Thermodynamics
If the temperature of A increases by 3 °C, and the temperature of B increases by 6 °C,
which of the following statements is true?
And here are our potential answers: These must be some creepy substances… [Gas appears]
Absorbing all this energy like dementors swallowing your soul… somebody should cast a patronus [Dementor appears]
Any object that increases in temperature is absorbing energy?
Oh….maybe we overreacted a little bit.
So to solve this problem, let’s take a look at this equation. [Finger points to equation]
Here, Q is the amount of heat or energy transferred when a material changes temperature, m is
the material’s mass, Cp is the heat capacity, and delta T is the change in
We know from the problem statement that substances A and B have the same mass.
They also both absorb the same amount of energy, 50 joules.
That means the only factors that can differ between them are the change in temperature [Thermometer rising in temperature]
and the heat capacity.
So let’s write that out as an equation, which looks a little something like….this.
And even though it looks complicated, you don't have to be Hermione Granger to solve
The problem tells us the temperature increase for substance A is 3 degrees Celsius, while [Finger points to temperature increase for substance A]
the temperature increase for substance B is 6 degrees Celsius.
If we reduce this equation and cancel out the units, we can see that the heat capacity
of material A is twice the heat capacity of material B. And that just happens to be answer
Well done. [Girl pours potion]
You know, if you went to Hogwarts, we’re pretty sure you’d be a Ravenclaw, you smarty